JP7137768B2 - motor controller - Google Patents

Description

The present invention relates to a motor control device that controls a motor that rotates a rotor using reluctance torque (hereinafter sometimes referred to as a "reluctance torque using motor"). The motor using reluctance torque includes not only a reluctance motor that rotates a rotor using only reluctance torque, but also a motor that rotates a rotor using reluctance torque and magnetic torque.

A reluctance motor that rotates a rotor using only reluctance torque is known. Reluctance motors include a switched reluctance motor (SRM) in which the stator and rotor have salient poles, and a synchronous reluctance motor (SynRM) in which the stator has the same structure as a brushless motor. .

A synchronous reluctance motor has salient poles only on the rotor of the stator and the rotor. In a synchronous reluctance motor, the salient poles of the rotor are divided into the direction of the salient poles where magnetic flux flows easily (hereinafter referred to as "d-axis direction") and the direction of non-salient poles where magnetic flux does not easily flow (hereinafter referred to as "q-axis direction"). ”). Therefore, the difference (L _d −L _q ) between the inductance in the d-axis direction (hereinafter referred to as “d-axis inductance L _d ”) and the inductance in the q-axis direction (hereinafter referred to as “q-axis inductance L _q ”) causes the reluctance torque is generated, and the rotor rotates due to this reluctance torque.

FIG. 9 of Patent Document 1 discloses a method of controlling a synchronous reluctance motor by vector control similar to that of a brushless motor. Specifically, an armature current command value corresponding to the motor torque to be generated by the synchronous reluctance motor and a current phase angle command value corresponding to the armature current command value are set. A d-axis current command value and a q-axis current command value are calculated based on the set armature current command value and current phase angle command value. Then, the synchronous reluctance motor is subjected to current feedback control based on the d-axis current command value and the q-axis current command value.

Japanese Patent Application Laid-Open No. 2015-23635

Masaru Hasegawa (Chubu University), Shinji Michiki (Nagoya University), Akiyoshi Satake (Okuma), Dohong Wang (Gifu University), "Drive circuit technology and drive control technology for permanent magnet motors and reluctance motors -6. Reluctance motor control" Technology- ”, Proceedings of the 2004 Institute of Electrical Engineers of Japan Industrial Applications Society Conference, I-119 to I-124 (2004)

In a synchronous reluctance motor, even if the armature current command value and current phase angle command value are held at predetermined values, the difference (L _d −L _q ) between the d-axis inductance L _d and the q-axis inductance L _q changes. Then, the motor torque changes (see equation (4) described later). In a synchronous reluctance motor, the difference (L _d −L _q ) between the d-axis inductance L _d and the q-axis inductance L _q changes depending on the armature current value and the rotor rotation angle. Therefore, the control method for the synchronous reluctance motor disclosed in Patent Document 1 has a problem that it is difficult to efficiently control the torque.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor control device capable of controlling a motor using reluctance torque with high efficiency.

A motor control device according to one embodiment of the present invention is a control device (31) for controlling a reluctance torque utilizing motor (18), wherein an armature current command value and a motor torque at the armature current command value are maximized. Tables (61, 62) storing the motor torque generated by the motor and the motor torque command value, which is the command value of the motor torque to be generated by the motor, are stored for the combination of the current phase angle command value of a first setting unit (41) for setting; an armature current command value and a current phase angle command value for generating a motor torque from the motor according to the motor torque command value set by the first setting unit; and a second setting unit (42) for setting based on the table. Note that alphanumeric characters in parentheses represent corresponding components and the like in embodiments described later, but the scope of the present invention is of course not limited to those embodiments. The same shall apply hereinafter in this section.

With this configuration, the ratio of the motor torque to the armature current is increased, so the synchronous reluctance motor can be driven with high efficiency.

In one embodiment of the present invention, it further includes rotation angle detection means (25, 53) for detecting the rotor rotation angle of the motor, and the table includes an armature current command value and a motor torque at the armature current command value. The motor torque generated from the motor is stored for each rotor rotation angle with respect to the combination with the current phase angle command value that maximizes the current phase angle, and the second setting unit stores the detected rotor torque detected by the rotation angle detection means. Based on the table, an armature current command value and a current phase angle command value for causing the motor to generate a motor torque corresponding to the motor torque command value set by the first setting unit are set for the rotation angle. .

In this configuration, an armature current command value and a current phase angle command value for generating motor torque from the electric motor in accordance with the motor torque command value are set at the detected rotor rotation angle detected by the rotation angle detection means. . This makes it possible to suppress torque fluctuations due to the rotor rotation angle.

In one embodiment of the present invention, the tables (61, 62) store the armature current command value and the maximum motor torque at the armature current command value when the motor is rotated in the first rotation direction. A first table (61) storing the motor torque generated by the motor for each rotor rotation angle and a second table (61) in which the motor rotates in the direction opposite to the first rotation direction for a combination of the current phase angle command value and the current phase angle command value. When rotating in the direction of rotation, the motor torque generated from the motor is calculated as the rotor torque with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at that armature current command value. and a second table (62) stored for each rotation angle. When the torque direction of the motor torque command value is the first rotation direction, the second setting unit generates a motor torque from the motor corresponding to the motor torque command value at the detected rotor rotation angle. The armature current command value and the current phase angle command value for causing the detected rotor rotation are set based on the first table, and when the torque direction of the motor torque command value is the second rotation direction, the detected rotor rotation An armature current command value and a current phase angle command value for causing the motor to generate a motor torque corresponding to the motor torque command value at an angle are set based on the second table.

According to this configuration, the first table (61) is applied when the electric motor rotates in the first rotation direction, and the electric motor rotates in the second rotation direction opposite to the first rotation direction. and a second table (62) that applies when As a result, even if the characteristics of the motor torque with respect to the rotor rotation angle are different when the electric motor rotates in the first rotation direction and when the electric motor rotates in the second rotation direction, the rotor rotation is It becomes possible to appropriately suppress torque fluctuations caused by angles.

In one embodiment of the present invention, a combination of a torque fluctuation reduction table (60) made up of the table and an armature current command value and a current phase angle command value that provide the maximum motor torque for each rotation speed of the motor is set. and a stored high output table (70), wherein the second setting unit selects one of the torque fluctuation reduction table and the high output table according to the rotational speed of the motor, and selects the selected table. is used to set the armature current command value and the current phase angle command value.

In one embodiment of the present invention, the motor is a reluctance torque utilization motor having two systems of stator coils (18A, 18B). The table shows the combination of a comprehensive armature current command value that includes the two systems and a current phase angle command value that maximizes the motor torque in the comprehensive armature current command value. It stores the motor torque generated from The second setting unit is configured to distribute a comprehensive armature current command value set based on the table to each of the systems. Then, the current supplied to the stator coil of each system is controlled based on the distributed armature current command value for each system and the current phase angle command value set by the second setting unit.

In one embodiment of the present invention, the control device is a control device for controlling a motor using reluctance torque having two systems of stator coils, and the motor torque command value set by the first setting unit is set by a first It further includes a torque command value distribution unit that distributes the motor torque command value for the system and the motor torque command value for the second system. The tables include a table for the first system and a table for the second system. The second setting unit uses the table for the first system and the motor torque command value for the first system to set an armature current command value and a current phase angle command value for the first system. A system command value setting unit, a table for the second system, and a motor torque command value for the second system are used to set an armature current command value and a current phase angle command value for the second system. and a command value setting unit for two systems. Based on the armature current command value and the current phase angle command value for the first system, the current supplied to the stator coil of the first system is controlled, and the armature current command value for the second system and the current phase angle command value are controlled. The current supplied to the stator coil of the second system is controlled based on the current phase angle command value.

In one embodiment of the present invention, the first system command value setting unit uses a second system abnormality table different from the first system table when there is an abnormality in the second system. , the armature current command value and the current phase angle command value for the first system; The armature current command value and the current phase angle command value for the second system are set using a first system abnormality table different from the table for the two systems.

The above and further objects, features and effects of the present invention will be made clear by the following description of embodiments with reference to the accompanying drawings.

1 is a schematic diagram showing a schematic configuration of an electric power steering device to which a motor control device according to an embodiment of the invention is applied; FIG. It is an illustration figure for demonstrating the structure of an electric motor. 2 is a schematic diagram showing an electrical configuration of an ECU in FIG. 1; FIG. 4 is a graph showing a setting example of a motor torque command value _Tm ^* with respect to a detected steering torque _Th . 4 is a graph showing an example of characteristic data of a motor torque _Tm with respect to a current phase angle β, obtained for each of a plurality of armature currents _Ia for a certain synchronous reluctance motor. FIG. 10 is a schematic diagram showing a part of an example of the contents of a normal conversion table; It is a schematic diagram showing an electrical configuration of a first modification of the ECU. FIG. 4 is a schematic diagram showing a part of an example of contents of a normal conversion table included in a high-output table; 4 is a flowchart for explaining the operation of a current command value setting unit; FIG. 5 is a schematic diagram showing an electrical configuration of a second modified example of the ECU; FIG. 4 is a schematic diagram showing a configuration of a current feedback control section of each system; FIG. 10 is a schematic diagram showing a part of an example of contents of a normal conversion table included in the comprehensive command value setting table; FIG. 11 is a schematic diagram showing an electrical configuration of a third modified example of the ECU; FIG. 10 is a schematic diagram showing a part of an example of contents of a forward conversion table included in a normal table for the first system; FIG. 11 is a schematic diagram showing a part of an example of contents of a forward rotation table included in a normal table for the second system;

FIG. 1 is a schematic diagram showing a schematic configuration of an electric power steering device to which a motor control device according to a first embodiment of the invention is applied.

The electric power steering apparatus 1 includes a steering wheel 2 as a steering member for steering a vehicle, a steering mechanism 4 for steering wheels 3 in conjunction with the rotation of the steering wheel 2, and a driver's steering wheel. and a steering assist mechanism 5 for assisting. The steering wheel 2 and steering mechanism 4 are mechanically connected via a steering shaft 6 and an intermediate shaft 7 .

Steering shaft 6 includes an input shaft 8 connected to steering wheel 2 and an output shaft 9 connected to intermediate shaft 7 . The input shaft 8 and the output shaft 9 are connected via a torsion bar 10 so as to be relatively rotatable.

A torque sensor 11 is provided around the steering shaft 6 . The torque sensor 11 detects the steering torque T _h applied to the steering wheel 2 based on relative rotational displacement amounts of the input shaft 8 and the output shaft 9 . A steering torque _Th detected by the torque sensor 11 is input to an ECU (Electronic Control Unit) 12 .

The steering mechanism 4 is a rack and pinion mechanism including a pinion shaft 13 and a rack shaft 14 as a steering shaft. The steered wheels 3 are connected to each end of the rack shaft 14 via tie rods 15 and knuckle arms (not shown). The pinion shaft 13 is connected to the intermediate shaft 7 . A pinion 16 is connected to the tip of the pinion shaft 13 .

The rack shaft 14 extends linearly along the left-right direction of the vehicle. A rack 17 that meshes with the pinion 16 is formed in the axially intermediate portion of the rack shaft 14 . The pinion 16 and rack 17 convert the rotation of the pinion shaft 13 into axial movement of the rack shaft 14 . By moving the rack shaft 14 in the axial direction, the steerable wheels 3 can be steered.

When the steering wheel 2 is steered (rotated), this rotation is transmitted to the pinion shaft 13 via the steering shaft 6 and intermediate shaft 7 . Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 by the pinion 16 and the rack 17 . As a result, the steerable wheels 3 are steered.

The steering assist mechanism 5 includes an electric motor 18 for steering assistance and a speed reducer 19 for transmitting the output torque of the electric motor 18 to the steering mechanism 4 . The electric motor 18 consists in this embodiment of a synchronous reluctance motor. The speed reducer 19 comprises a worm gear mechanism including a worm gear 20 and a worm wheel 21 meshing with the worm gear 20 . The speed reducer 19 is housed within the gear housing 22 .

The worm gear 20 is rotationally driven by the electric motor 18 . The worm wheel 21 is connected to the steering shaft 6 so as to rotate integrally therewith. The worm wheel 21 is rotationally driven by the worm gear 20 .

When the worm gear 20 is rotationally driven by the electric motor 18, the worm wheel 21 is rotationally driven and the steering shaft 6 is rotated. Rotation of the steering shaft 6 is transmitted to the pinion shaft 13 via the intermediate shaft 7 . Rotation of the pinion shaft 13 is converted into axial movement of the rack shaft 14 by the rack and pinion mechanism. As a result, the steerable wheels 3 are steered. In other words, the steering assistance by the electric motor 18 is enabled by rotationally driving the worm gear 20 by the electric motor 18 .

A rotation angle of the rotor of the electric motor 18 (hereinafter referred to as "rotor rotation angle") is detected by a rotation angle sensor 25 such as a resolver. An output signal of the rotation angle sensor 25 is input to the ECU 12 . The electric motor 18 is controlled by an ECU 12 as a motor control device.

FIG. 2 is an illustrative view for explaining the configuration of the electric motor 18. As shown in FIG.

The electric motor 18 is a synchronous reluctance motor as described above, and as illustrated in FIG. and a stator 105 having wires. The armature winding is formed by connecting a U-phase stator coil 101, a V-phase stator coil 102, and a W-phase stator coil 103 in a star configuration.

A three-phase fixed coordinate system (UVW coordinate system) is defined in which the U-axis, V-axis and W-axis are taken in the direction of the stator coils 101, 102 and 103 of each phase. In addition, the d-axis direction is taken in the direction of the salient poles where the magnetic flux easily flows from the rotation center side of the rotor 100 to the outer periphery, and the q-axis direction is taken in the direction of the non-salient poles where the magnetic flux does not easily flow from the rotation center side of the rotor 100 to the outer periphery. A two-phase rotating coordinate system (dq coordinate system, real rotating coordinate system) with an axial direction is defined. The dq coordinate system is a real rotation coordinate system according to the rotation angle (rotor rotation angle) θ of the rotor 100 .

In this embodiment, the rotor rotation angle (electrical angle) .theta. is defined as the rotation angle of The direction of the one salient pole serving as a reference is called the +d-axis direction, and the direction of the other adjacent salient pole is called the -d-axis direction. The axis rotated by +90 electrical degrees with respect to the +d axis is called the +q axis, and the axis rotated by -90 electrical degrees with respect to the +d axis is called the -q axis. The magnetic poles (N pole and S pole) generated in the rotor 100 (salient pole portion) are determined by the direction of the current vector _Ia in the dq coordinate system. In this embodiment, the forward rotation direction of the electric motor 18 corresponds to the counterclockwise (CCW) direction of the rotor 100 in FIG. 2, and the reverse rotation direction of the electric motor 18 corresponds to the clockwise (CW) direction of the rotor 100 in FIG. shall correspond.

Coordinate conversion between the UVW coordinate system and the dq coordinate system is performed by using the rotor rotation angle θ (see, for example, formulas (1) and (2) in Japanese Patent Application Laid-Open No. 2009-137323).

In this specification, the current flowing through the armature winding will be referred to as "armature current" or "motor current." A current vector _Ia in the dq coordinate system is a vector of current flowing through the armature winding (armature current vector). β is the current phase angle, which is the phase difference between the armature current vector _Ia and the d-axis. id is the _d -axis current and is expressed by id= _Ia · _cosβ . iq is the _q -axis current and is expressed by _iq = _Ia ·sinβ.

FIG. 3 is a schematic diagram showing an electrical configuration of the ECU 12 of FIG. 1. As shown in FIG.

The ECU 12 includes a microcomputer 31, a drive circuit (inverter circuit) 32 controlled by the microcomputer 31 to supply electric power to the electric motor 18, and a U-phase current, a V-phase current and a W-phase current flowing through the electric motor 18. and current sensors 33, 34, 35 for detection.

The microcomputer 31 has a CPU and memory, and functions as a plurality of functional processing units by executing predetermined programs. The memory includes ROM, RAM, non-volatile memory 40, and the like. The plurality of function processing units include a torque command value setting unit 41, a current command value setting unit 42, a current vector calculation unit 43, a d-axis current deviation calculation unit 44, a q-axis current deviation calculation unit 45, a d Axis PI (proportional integral) control unit 46 , q-axis PI (proportional integral) control unit 47 , voltage limiting unit 48 , two-phase/three-phase coordinate conversion unit 49 , PWM control unit 50 , and current detection unit 51 , a three-phase/two-phase coordinate conversion unit 52 and a rotation angle calculation unit 53 are included.

The rotation angle calculator 53 calculates the rotation angle (rotor rotation angle θ) of the rotor of the electric motor 18 based on the output signal of the rotation angle sensor 25 . calculated by the rotation angle calculator 53 is given to the current command value setting unit 42 and the coordinate converters 49 and 52 .

Based on the output signals of the current sensors 33, 34, and 35, the current detection unit 51 detects phase currents iU, iV, and iW of the _U -phase, the _V -phase, and the _W -phase (hereinafter collectively referred to as "three-phase detection currents"). i _U , i _V , i _W ”).

The torque command value setting unit 41 sets a motor torque command value T _m ^* , which is the command value of the motor torque to be generated by the electric motor 18 . Specifically, the torque command value setting unit 41 sets the motor torque command value T _m ^* based on the steering torque detected by the torque sensor 11 (detected steering torque T _h ). A setting example of the motor torque command value T _m ^* with respect to the detected steering torque T _h is shown in FIG. As for the detected steering torque _Th , for example, the torque for steering to the left is taken as a positive value, and the torque for steering to the right is taken as a negative value. The direction of the motor torque for assisting the leftward steering of the electric motor 18 corresponds to the forward rotation direction of the electric motor 18, and the direction of the motor torque for assisting the rightward steering corresponds to the direction of the electric motor 18. corresponding to the reverse direction of The motor torque command value T _m ^* is a positive value when the electric motor 18 should generate a steering assist force for left steering, and the electric motor 18 should generate a steering assist force for right steering. It is sometimes taken as a negative value.

The motor torque command value T _m ^* takes a positive value for a positive value of the detected steering torque T _h , and takes a negative value for a negative value of the detected steering torque T _h . When the detected steering torque T _h is zero, the motor torque command value T _m ^* is zero. Then, the larger the absolute value of the detected steering torque _{Th, the larger the absolute value of the motor torque command value Tm *} ^. Accordingly, the steering assist force can be increased as the absolute value of the detected steering torque _Th increases.

The torque command value setting unit 41 uses, for example, a map storing the relationship between the steering torque T _h and the motor torque command value T _m ^* as shown in FIG. A motor torque command value _Tm ^* corresponding to _Th is set. Motor torque command value T _m ^* set by torque command value setting unit 41 is provided to current command value setting unit 42 and current vector calculation unit 43 .

The nonvolatile memory 40 stores an armature current/current phase angle setting table for forward rotation (CCW) (hereinafter referred to as "forward rotation table 61") and an armature current/current phase angle setting table for reverse rotation (CW). A table (hereinafter referred to as "reversing table 62") is stored. Details of these tables 61 and 62 will be described later.

The current command value setting unit 42 sets the motor torque command value T _m ^* given from the torque command value setting unit 41, the rotor rotation angle θ given from the rotation angle calculation unit 53, the forward rotation table 61 and the reverse rotation table 61, _Armature current command value _Ia ^* ( _Ia ^* > 0) and current phase angle command value β ^{* (} β ^* > 0). Details of the current command value setting unit 42 will be described later.

The current vector calculation unit 43 calculates the armature current command value _Ia ^* and the current phase angle command value β ^* set by the current command value setting unit 42, and the motor torque command value T given from the torque command value setting unit 41. A d-axis current command value i _d ^* and a q-axis current command value i _q ^* are calculated based on the sign of _m ^* . Specifically, the current vector calculator 43 calculates the d-axis current command value i _d ^* based on the following equation (1).

i _d ^* =I _a ^* ·cos β ^* (1)
Also, the current vector calculation unit 43 calculates the q-axis current command value i _q ^* based on the following equation (2a) or (2b).

When T _m ^* ≧0, i _q ^* =I _a ^* ·sin β ^* (2a)
When T _m ^* < 0, i _q ^* = I _a ^* · sin(-β ^* ) (2b)
The _d -axis current command value id ^* and the q-axis current command value _iq ^* may be collectively referred to as "two-phase command currents _id ^* and _iq ^* ".

Three-phase detection currents i _U , i _V , and i _W detected by current detection section 51 are provided to three-phase/two-phase coordinate conversion section 52 . The three-phase/two-phase coordinate conversion unit 52 uses the rotor rotation angle θ calculated by the rotation angle calculation unit 53 to convert the three-phase detection currents i _U , i _V , and i _W into d-axis currents on the dq coordinates. _id and _{q-axis current iq (hereinafter collectively referred to as "two-phase detection currents id and iq " )} . The d-axis current id obtained by the three-phase/two-phase coordinate conversion section 52 is applied to the _d -axis current deviation calculation section 44 . The q-axis current iq obtained by the three-phase/two-phase coordinate conversion section 52 is supplied to the _q -axis current deviation calculation section 45 .

The d-axis current deviation calculator 44 calculates a deviation Δid (= _id ^* _-id ) of the _d -axis current i _d with respect to the d-axis current command value i _d ^* . The d-axis PI control unit 46 calculates the d-axis command voltage v _d ′ ^* by performing PI (proportional integral) calculation on the current deviation Δid calculated by the _d -axis current deviation calculation unit 44 . This d-axis command voltage v _d ′ ^* is applied to the voltage limiter 48 .

The q-axis current deviation calculator 45 calculates a deviation Δi _q (=i _q ^* -i _q ) of the q-axis current i _q with respect to the q-axis current command value i _q ^* . The q-axis PI control unit 47 calculates the q-axis command voltage v _q ′ ^* by performing PI (proportional integral) calculation on the current deviation Δi _q calculated by the q-axis current deviation calculation unit 45 . This q-axis command voltage v _q ′ ^* is applied to the voltage limiter 48 .

The voltage limiting unit 48 is provided to avoid a state (voltage saturation state) in which the induced voltage generated in the electric motor 18 becomes higher than the power supply voltage and current cannot flow to the electric motor 18 . For example, the voltage limiter 48 limits the d-axis command voltage v _d ′ ^* to a preset d-axis voltage command maximum value or less, and limits the q-axis command voltage v _q ′ ^* to a preset q-axis voltage command value. Limit to below the maximum value. The d-axis command voltage v _d ^* and the q-axis command voltage v _q ^* after the limit processing by the voltage limiter 48 are applied to the two-phase/three-phase coordinate converter 49 .

The two-phase/three-phase coordinate conversion unit 49 uses the rotor rotation angle θ calculated by the rotation angle calculation unit 53 to convert the d-axis command voltage v _d ^* and the q-axis command voltage v _q ^* into U-phase and V-phase and _W -phase indicated voltages _vU ^* , _vV ^* , vW ^* . The command voltages vU ^* , vV ^* , _vW ^* of the _U -phase, V-phase and _W -phase are collectively referred to as "three-phase command voltages _vU ^* , _vV ^* , _vW ^* ".

PWM control unit 50 outputs a U-phase PWM control signal, a V-phase PWM control signal, and a W-phase PWM control signal having duty ratios corresponding to _U -phase command voltage vU ^* , _V -phase command voltage vV ^* , and _W -phase command voltage vW ^* , respectively. A PWM control signal is generated and supplied to the drive circuit 32 .

The drive circuit 32 consists of a three-phase inverter circuit corresponding to the U-phase, V-phase and W-phase. The power elements constituting this inverter circuit are controlled by the PWM control signals given from the PWM control section 50, so that the voltages corresponding to the three-phase command voltages _vU ^* , _vV ^* , _vW ^* are applied to the electric motor 18. It will be applied to the stator coil of each phase.

The current deviation calculators 44 and 45 and the PI controllers 46 and 47 constitute current feedback control means. The current feedback control means controls the motor current (armature current) flowing through the electric motor 18 so as to approach the two-phase command currents _{id* and iq} ^* _calculated ^by the current vector calculation unit 43. .

Hereinafter, the forward rotation table 61, the reverse rotation table 62, and the current command value setting unit 42 will be described in detail.

In order to drive the electric motor 18 with high efficiency, the electric motor 18 should be controlled so as to increase the ratio of the motor torque to the armature current.

A motor torque _Tm in a synchronous reluctance motor having a pole pair _{number Pn} is expressed by the following equation (3).

T _m = P _n · (L _d - L _q ) · i _d · i _q (3)
Ld is the _d -axis inductance [H] and Lq is the _q -axis inductance [H]. Also, id is the _d -axis current [A] and iq is the _q -axis current [A].

Assuming that the magnitude of the armature current is _Ia and the current phase angle is β, _iq = _Ia ·sin β and id = _Ia · _{cosβ .} expressed. The current phase angle β is the phase difference between the armature current vector and the d-axis.

T _m =(1/2)·P _n ·(L _d −L _q )·I _a ² sin2β (4)
Therefore, if the _d -axis inductance Ld and the _q -axis inductance Lq do not fluctuate, the motor torque _Tm becomes maximum when the current phase angle β is 45 degrees. However, in the synchronous reluctance motor, the _d -axis inductance Ld and the _q -axis inductance _Lq fluctuate under the influence of the magnetic saturation of the rotor core and stator core. not necessarily the maximum.

FIG. 5 is a graph showing characteristic data of the motor torque _Tm with respect to the current phase angle β obtained for each of a plurality of armature currents _Ia in a certain synchronous reluctance motor. The characteristic data shown in FIG. 5 is obtained by diverting the data published in Non-Patent Document 1 above. However, in FIG. 5, the horizontal axis represents the current phase _angle β, and the vertical axis represents the motor torque _{Tm .} ing.

As shown in FIG. 5, the current phase angle β that maximizes the motor torque _Tm differs depending on the magnitude of the armature current _Ia . In the example of FIG. 5, as the armature current _Ia increases, the current phase angle β that maximizes the motor torque _Tm increases. In order to drive the electric motor 18 with high efficiency, it is preferable to set the current phase angle β at which the motor torque _Tm is maximized with respect to the armature current command value _Ia ^* .

FIG. 6 is a schematic diagram showing a part of an example of the contents of the forward conversion table 61. As shown in FIG.

The forward rotation table 61 contains the armature current command value _Ia ^* when the electric motor 18 is rotated in the forward direction, and the current at which the motor torque _Tm is maximized at the armature current command value _Ia ^* . A motor torque T _m [Nm] generated from the electric motor 18 is stored for each rotor rotation angle θ in combination with the phase angle command value β ^* .

In this example, the N armature current command values _Ia ^* have a relationship of _Ia ^* ₁ < _Ia ^* ₂ <... _Ia ^* _N . The _M rotor rotation angles .theta. are set in predetermined angular increments from 0.degree. The motor torque _Tm is set to increase as the armature current command value _Ia ^* increases.

Such a normal rotation table 61 is created, for example, as follows. If a predetermined armature current command value _Ia ^* and a predetermined current phase angle command value β ^* are given to the current vector calculation unit 43 of the motor control circuit as shown in FIG. , the armature current command value _Ia ^* , the current phase angle command value β ^* , and the two-phase command currents _id ^* and _iq ^* corresponding to the signs, the electric motor 18 is driven forward. The motor torque _Tm generated from the electric motor 18 and the rotor rotation angle θ are obtained while the electric motor 18 is driven to rotate forward. As a result, the motor torque _Tm for each rotor rotation angle θ with respect to the combination of the predetermined armature current command value _Ia ^* and the predetermined current phase angle command value β ^* is obtained. The motor torque _Tm is measured using a measuring device (not shown).

By conducting such an experiment for each of a plurality of current phase angle command values β ^* , the rotor rotation angle for each combination of the predetermined armature current command value I _a ^* and a plurality of current phase angle command values β ^* is obtained. Acquire the data of the motor torque _Tm for each θ. Based on the data thus acquired, the current phase angle command value β ^* that maximizes the motor torque _Tm with respect to the predetermined armature current command value _Ia ^* is specified.

By conducting the above-described experiment for each of _a plurality of armature current command values I _a ^* , the armature current command value I _a ^* and ^the motor The data of the motor torque _Tm for each rotor rotation angle θ is acquired for the combination with the current phase angle command value β ^* that maximizes the torque _Tm . As a result, data for creating the normal rotation table 61 is obtained.

Although not shown, the reverse rotation table 62 stores the armature current command value _Ia ^* when the electric motor 18 is rotated in the reverse direction, and the maximum motor torque _Tm at the armature current command value _Ia ^* . The motor torque T _m [Nm] generated from the electric motor 18 is stored for each rotor rotation angle θ with respect to the combination with the current phase angle command value β ^* that gives

The reverse rotation table 62 is produced by conducting experiments similar to those conducted to produce the forward rotation table 61 . However, when creating the reverse rotation table 62, unlike the case of creating the forward rotation table 61, the current vector calculation unit 43 is given a sign indicating the reverse rotation direction during the experiment. As a result, the electric motor 18 is rotationally driven in the reverse direction during the experiment.

Next, the operation of the current command value setting section 42 will be described in detail. In the following description, the latest rotor rotation angle θ calculated by the rotation angle calculator 53 will be referred to as "current rotor rotation angle θ".

The current command value setting unit 42 first selects the rotation direction tables 61 and 62 from the forward rotation table 61 and the reverse rotation table 62 according to the sign of the motor torque command value T _m ^* . Based on the selected tables 61 and 62, the current command value setting unit 42 provides an armature for causing the electric motor 18 to generate a motor torque corresponding to the motor torque command value _Tm ^* at the current rotor rotation angle θ. A current command value _Ia ^* and a current phase angle command value β ^* are set.

Specifically, the current command value setting unit 42 selects one of a plurality of motor torques _Tm corresponding to the current rotor rotation angle θ in the selected tables 61 and 62, and selects a motor torque command value having the same magnitude as the motor torque command value _Tm ^*. to retrieve the motor torque T _m of . When the current command value setting unit 42 can retrieve the motor torque _Tm having the same magnitude as the motor torque command value _Tm ^* , the armature current corresponding to the motor torque _Tm is obtained from the tables 61 and 62. The command value I _a ^* and the current phase angle command value β ^* are read out and set in the current vector calculator 43 .

On the other hand, when the motor torque _Tm having the same magnitude as the motor torque command value _Tm ^* cannot be retrieved, the current command value setting unit 42 performs the following processing. The current command value setting unit 42 selects a motor torque value smaller than and closest to the motor torque command value T _m ^* from among a plurality of motor torques T _m corresponding to the current rotor rotation angle θ in the selected tables 61 and 62 . The armature current command value _Ia ^* and the current phase angle command value β ^* corresponding to the torque _Tm (hereinafter referred to as "first motor torque _Tm1 ") are read. Further, the current command value setting unit 42 selects the motor torque command value Tm* that is larger than the motor torque command value _Tm ^* and closest to it from among the plurality of motor torques _Tm corresponding to the current rotor rotation angle θ in the tables 61 and 62 . The armature current command value _Ia ^* and the current phase angle command value β ^* corresponding to the motor torque _Tm (hereinafter referred to as "second motor torque _Tm2 ") are read. Then, the current command value setting unit 42 linearly interpolates the read two sets of armature current command value _Ia ^* and current phase angle command value β ^* to obtain an armature value corresponding to the motor torque command value _Tm ^* . A current command value _Ia ^* and a current phase angle command value β ^* are calculated.

This linear interpolation will be specifically described. The armature current command value _Ia ^* and the current phase angle command value β ^* corresponding to the first motor torque _Tm1 are set to _Ia ^* 1 and β ^* 1, respectively, and corresponding to the second motor torque _Tm2 The armature current command value _Ia ^* and the current phase angle command value β ^* are set to _Ia ^* 2 and β ^* 2, respectively. Also, T _m 2 - T _m 1 = ΔT _m , I _a ^* 2 - I _a ^* 1 = ΔI _a ^* , and β ^* 2 - β ^* 1 = Δβ ^* .

The current command value setting unit 42 calculates the armature current command value _Ia ^* and the current phase angle command value β ^* corresponding to the motor torque command value _Tm ^* based on the following equations (5) and (6). . Then, the current command value setting unit 42 sets the obtained armature current command value I _a ^* and current phase angle command value β ^* in the current vector calculation unit 43 .

_Ia ^* =( _ΔIa ^* / _ΔTm )·( _Tm ^* _−Tm1 )+ _Ia ^* 1 (5)
β ^* =(Δβ ^* / _ΔTm )·( _Tm ^* _−Tm1 )+β ^* 1 (6)
In the above-described embodiment, the ^optimal _armature current command value I _a ^* and current phase angle command value β ^* can be set. This makes it possible to suppress torque fluctuations caused by the rotor rotation angle θ.

Further, according to the above-described embodiment, the forward rotation table 61 applied when the electric motor 18 rotates in the forward direction and the reverse rotation table 61 applied when the electric motor 18 rotates in the reverse direction are provided. and a table 62 for use. As a result, even if the characteristics of the motor torque _Tm with respect to the rotor rotation angle θ are different between when the electric motor 18 rotates in the forward direction and when the electric motor 18 rotates in the reverse direction, in each direction of rotation, It becomes possible to appropriately suppress torque fluctuations caused by the rotor rotation angle θ.
[First modification]
A first modification of the ECU will be described below.

FIG. 7 is a schematic diagram showing the electrical configuration of a first modified example of the ECU. In FIG. 7, the same reference numerals as in FIG. 3 denote the parts corresponding to the parts in FIG. 3 described above.

In the ECU 12 of FIG. 7, a rotational speed calculator 54 is added as compared with the ECU 12 of FIG. In the ECU 12 of FIG. 7, high output tables 71 and 72 are stored in the nonvolatile memory 40 in addition to the armature current/current phase angle setting tables 61 and 62 described above. Further, in the ECU 12 of FIG. 7, a current command value setting section 142 is used instead of the current command value setting section 42 of FIG. Other configurations of the ECU 12 in FIG. 7 are the same as those of the ECU 12 in FIG.

The rotation speed calculation unit 54 calculates the rotation speed ω [rpm] of the electric motor 18 by time differentiating the rotor rotation angle θ calculated by the rotation angle calculation unit 53 .

When the electric motor 18 is controlled based on the forward rotation table 61 and the reverse rotation table 62, control with small torque variation (torque variation reduction control) can be performed. It may be referred to as a torque fluctuation reduction table 60 .

In addition to the torque fluctuation reduction table 60, the nonvolatile memory 40 stores a high output table 70. FIG. The high output table 70 includes a forward rotation table 71 and a reverse rotation table 72 . As shown in FIG. 8, the forward rotation table 71 stores an armature current command value _Ia that maximizes the motor torque for each rotational speed of the electric motor 18 when the electric motor 18 is rotated in the forward rotation direction. A combination of ^* and the current phase angle command value β ^* is stored. In the reverse rotation table 72, the armature current command value _Ia ^* and the current phase angle command value β that maximize the motor torque are stored for each rotational speed of the electric motor 18 when the electric motor 18 is rotated in the reverse direction. A combination of ^* is stored.

FIG. 9 is a flow chart for explaining the operation of the current command value setting unit 142. As shown in FIG. The processing in FIG. 9 is repeatedly executed at predetermined calculation cycles. In the following description, the latest rotational speed ω calculated by the rotational speed calculator 54 is referred to as "current rotational speed ω".

The current command value setting unit 142 determines whether or not the current rotation speed ω is equal to or less than a predetermined rotation speed _ωth (step S1). The predetermined rotational speed ω _th is, for example, the boundary between a constant torque region (low speed region) where the torque is substantially constant and a constant output region where the rotational speed is higher than the constant torque region in the speed-torque characteristics of the electric motor 18. It is set to the rotation speed near the point.

If the current rotation speed ω is equal to or less than the predetermined rotation speed _ωth (step S1: YES), the current command value setting unit 42A sets the motor torque command value T at the current rotor rotation angle θ based on the torque fluctuation reduction table 60. An armature current command value _Ia ^* and a current phase angle command value β ^* for generating a motor torque corresponding to _m ^* from the electric motor 18 are set (step S2: YES). At this time, which of the forward rotation table 61 and the reverse rotation table 62 is used is determined based on the sign of the motor torque command value T _m ^* . Then, the processing in the current calculation cycle ends.

If it is determined in step S1 that the current rotational speed ω is greater than the predetermined rotational speed _ωth , the current command value setting unit 142 determines that the motor torque is maximum at the current rotational speed ω based on the high output table 70. An armature current command value _Ia ^* and a current phase angle command value β ^* are set (step S3: YES). At this time, which of the forward rotation table 71 and the reverse rotation table 72 is used is determined based on the sign of the motor torque command value T _m ^* . Then, the processing in the current calculation cycle ends.

In this embodiment, when the rotation speed ω of the electric motor 18 is equal to or lower than the predetermined rotation speed _ωth , control can be performed with priority given to reducing torque fluctuations. On the other hand, when the rotation speed ω of the electric motor 18 is higher than the predetermined rotation speed _ωth , control can be performed with priority given to increasing the output. As a result, high output can be obtained in the high speed range of the electric motor 18 .
[Second modification]
A second modification of the ECU 12 will be described. The ECU 12 according to the second modification is a control unit for controlling a synchronous reluctance motor having two systems of stator coils.

Torque generated by a synchronous reluctance motor having two stator coils will be described.

The basic torque formula of the synchronous reluctance motor is represented by formula (3) mentioned above.

T _m = P _n · (L _d - L _q ) · i _d · i _q (3)
Therefore, the torques T _m1 and T _m2 generated when the first system and the second system are driven separately are given by the following equations (7) and (8). where i _d1 and i _q1 represent the d-axis current and q-axis current of the first system, respectively, and i _d2 and i _q2 represent the d-axis current and q-axis current of the second system, respectively.

T _m1 = P _n · (L _d - L _q ) · i _d1 · i _q1 (7)
T _m2 = P _n · (L _d - L _q ) · i _d2 · i _q2 (8)
Assuming that the first system and the second system do not affect each other, the torque _Tm when the first system and the second system are driven at the same time is given by the following equation (9). If the two systems are driven with the same _d -axis current id (= _id1 = _id2 ) and the same _q -axis current iq (= _iq1 = _iq2 ), the following equation (10) is obtained.

_{( 9 ) _ _ _ _ _ _ _ _ _ _
Tm} =Tm1+ _Tm2 = _2Pn .( _Ld - _{Lq ) .id.iq (} 10)
However, depending on the arrangement method of the stator coils of the first system and the stator coils of the second system, each system will be affected by the magnetic flux applied to the rotor by the stator coils of the other systems. In such a case, the torque _Tm1 generated by the first system and the torque _Tm2 generated by the second system are expressed by the following equations (11) and (12), for example.

T _m1 =P _n {(L _d −L _q )· _id1 ·i _q1 +(L _d −L _q )· _id2 ·i _q1 } (11)
T _m2 =P _n {(L _d −L _q )·i _d2 ·i _q2 +(L _d −L _q )·i _d1 ·i _q2 } (12)
The second term in equation (11) represents the torque generated by the interlinkage with the magnetic flux (L _d −L _q )·i _d2 applied to the rotor by the second system. Similarly, the second term in equation (12) represents the torque generated by the interlinkage with the magnetic flux (L _d −L _q )·i _d1 applied to the rotor by the first system.

Therefore, the _{torque Tm obtained} by driving the first system and the second system at the same time is given by the following equation (13). =i _d , i _q1 =i _q2 =i _q , the following equation (14) is obtained.

_Tm = _Tm1 + _Tm2
=P _n {(L _d −L _q )·i _d1 ·i _q1 +(L _d −L _q )·i _d2 ·i _q1 }
+P _n {(L _d −L _q )·i _d2 ·i _q2 +(L _d −L _q )·i _d1 ·i _q2 } (13)
_Tm =Tm1+ _Tm2 = _{4Pn .} ( _Ld - _{Lq ) .id.iq} (14)
That is, theoretically, a torque twice as large as that obtained by equation (10) can be obtained.

As described above, in a synchronous reluctance motor having two systems of stator coils, the motor torque when both systems are driven simultaneously is not the sum of the motor torques when each system is driven independently. For this reason, by conducting experiments with each system driven independently, an armature current/current phase angle setting table is created for each system, and these tables are used to set the armature current command value and current phase angle for each system. Even if the angle command value is set, the motor torque corresponding to the motor torque command value T _m ^* cannot be output.

Therefore, the ECU 12 according to the second modification provides a motor control method capable of outputting a motor torque corresponding to the motor torque command value T _m ^* to a synchronous reluctance motor having two systems of stator coils. do.

FIG. 10 is a schematic diagram showing the electrical configuration of a second modification of the ECU.

The electric motor 18 is a synchronous reluctance motor including a first system stator coil 18A and a second system stator coil 18B. The stator coils 18A and 18B of each system have U-phase, V-phase and W-phase stator coils, respectively.

ECU 12 includes a microcomputer 81 , a first system drive circuit 82 , a second system drive circuit 83 , first system current sensors 84 , 85 , 86 and second system current sensors 87 , 88 , 89 . The first system drive circuit 82 and the second system drive circuit 83 are, for example, three-phase inverter circuits. The first system current sensors 84, 85, 86 include three current sensors that detect the current of each UVW phase of the first system. The second system current sensors 87, 88, and 89 include three current sensors that detect the current of each UVW phase of the second system. A rotation angle sensor 25 for detecting the rotation angle of the rotor is attached to the electric motor 18 .

The microcomputer 81 has a CPU and memory, and functions as a plurality of functional processing units by executing predetermined programs. The memory includes ROM, RAM, non-volatile memory 40, and the like. The multiple function processing units include a torque command value setting unit 91, a comprehensive command value setting unit 92, a first system control unit 93A, and a second system control unit 93B.

A torque command value setting unit 91 sets a motor torque command value T _m ^* , which is a command value of the motor torque to be generated by the electric motor 18, similarly to the torque command value setting unit 41 in FIG. The motor torque command value T _m ^* set by the torque command value setting section 91 is given to a comprehensive command value setting section 92 and current vector calculation sections 43A and 43B (see FIG. 10), which will be described later.

The nonvolatile memory 40 stores a global command value setting table 111 for setting global command values for the entire system including the two systems. The comprehensive command value is an armature current command value (hereinafter referred to as "comprehensive current command value I _{a, total} ^* "; I _{a, total} ^* > 0) and a current phase angle command for the entire system including the two systems. (hereinafter referred to as “general phase angle command value β _total ^* ”; β _total ^* >0).

The comprehensive command value setting table 111 includes a forward rotation (CCW) table (hereinafter referred to as "forward rotation table 111a") and a reverse rotation (CW) table (hereinafter referred to as "reverse rotation table 111b"). include. Details of these tables 111a and 111b will be described later.

A comprehensive command value setting unit 92 sets a motor torque command value T _m ^* , a rotor rotation angle θ given from a rotation angle calculation unit 53A (see FIG. 11) described later, and a motor torque command value T from tables 111a and 111b. A global current command value I _{a, total} ^* and a global phase angle command value β _total ^* are set based on a table corresponding to the sign of _m ^* . Details of the comprehensive command value setting unit 92 will be described later.

The first system control unit 93A controls the first system drive circuit 82 based on the comprehensive current command value _{Ia, total} ^* and the comprehensive phase angle command value β _total ^* , and supplies the first system stator coil 18A with the current command value Ia, total*. controls the current drawn. The second system control unit 93B controls the second system drive circuit 83 based on the comprehensive current command value _{Ia, total} ^* and the comprehensive phase angle command value β _total ^* , and supplies the second system stator coil 18B with the current command value Ia, total*. controls the current drawn.

First system control unit 85A and second system control unit 85B include current command value setting units 42A and 42B, current vector calculation units 43A and 43B, and current feedback control units 94A and 94B.

As shown in FIG. 11, the current feedback controllers 94A and 94B include d-axis current deviation calculators 44A and 44B, q-axis current deviation calculators 45A and 45B, d-axis PI controllers 46A and 46B, and q-axis controllers 46A and 46B. PI control units 47A, 47B, voltage limiting units 48A, 48B, two-phase/three-phase coordinate conversion units 49A, 49B, PWM control units 50A, 50B, current detection units 51A, 51B, three-phase/two-phase It includes coordinate conversion units 52A and 52B and rotation angle calculation units 53A and 53B.

Returning to FIG. 10, the current command value setting units 42A and 42B use the following equations (15) and (16) based on the comprehensive current command value _{Ia, total} ^* and the comprehensive phase angle command value β _total ^* . , armature current command values I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* for the first and second systems.

I _a1 ^* = I _{a, total} ^* /2, β ₁ ^* = β _total ^* (15)
I _a2 ^* = I _{a, total} ^* /2, β ₂ ^* = β _total ^* (16)
Current vector calculation units 43A and 43B calculate d-axis current command values i _d1 ^* and i _d2 ^* and q-axis current command values i _q1 ^* and i _q2 ^* for the first and second systems. Specifically, the current vector calculation units 43A and 43B calculate the d-axis current command values _id1 ^* and _id2 ^* based on the following equations (17) and (18).

i _d1 ^* =I _a1 ^* ·cos β ₁ ^* (17)
id2 ^* = _Ia2 ^* _{.cosβ2 *} ⁽ 18)
Further, the current vector calculation unit 43A calculates the q-axis current command value i _q1 ^* based on the following equations (19a) and (19b), and the current vector calculation unit 43B calculates the following equations (20a) and (20b). Based on this, the q-axis current command value i _q2 ^* is calculated.

When T _m ^* ≧0, i _q1 ^* =I _a1 ^* ·sinβ ₁ ^* (19a)
When T _m ^* < 0, i _q1 ^* = I _a1 ^* · sin(-β ₁ ^* ) (19b)
When T _m ^* ≧0, i _q2 ^* =I _a2 ^* ·sinβ ₂ ^* (20a)
When T _m ^* < 0, i _q2 ^* = I _a2 ^* · sin(-β ₂ ^* ) (20b)
Referring to FIG. 11 , rotation angle calculation units 53A and 53B calculate the rotation angle (rotor rotation angle θ) of the rotor of electric motor 18 based on the output signal of rotation angle sensor 25 .

Based on the output signals of current sensors 84, 85, 86; 87, 88, 89, current detection units 51A and 51B detect phase currents _iU1 , _iV1 , _iW1 , and iU2 of _U -phase, V-phase, and W-phase. , i _V2 , i _W2 are calculated. The three-phase/two-phase coordinate conversion units 52A and 52B use the rotor rotation angles θ calculated by the rotation angle calculation units 53A and 53B to obtain three-phase currents i _U1 , i _V1 , i _W1 ; i _U2 , i _V2 , _iW2 are converted into d-axis currents _id1 , _id2 and q-axis currents _iq1 , _iq2 .

The d-axis current deviation calculators 44A and 44B calculate the deviation _Δid1 (= _id1 ^* ) between the _d -axis current command values _id1 ^* and _id2 ^* and the d-axis currents _id1 and id2 flowing in the stator coils of the own system. −i _d1 ) and Δi _d2 (=i _d2 ^* −i _d2 ). The _q -axis current deviation calculation units 45A and _{45B calculate the} deviation ^Δi _q1 ⁽ =i _q1 ^* −i _q1 ) and Δi _q2 (=i _q2 ^* −i _q2 ).

The d-axis PI control units 46A and 46B perform PI (proportional integral) calculation on the d-axis current deviations Δi _d1 and Δi _d2 to obtain the d-axis command voltage v _d1 ′ for the first system and the second system. ^* , v _d2 ' ^* are calculated. The q-axis PI control units 47A and 47B perform PI calculations on the q-axis current deviations Δi _q1 and Δi _q2 to obtain q-axis command voltages v _q1 ′ ^* and v _q2 for the first and second systems. ' Calculate ^* .

The voltage limiting units 48A and 48B limit the d-axis command voltages v _d1 ′ ^* and v _d2 ′ ^* to, for example, a preset d-axis voltage command maximum value or less, and the q-axis command voltages v _q1 ′ ^* and v _q2 ' ^* is limited to a preset q-axis voltage command maximum value or less. The d-axis command voltages v _d1 ^* , v _d2 ^* and the q-axis command voltages v _q1 ^* , v _q2 ^* after the limit processing by the voltage limiters 48A, 48B are applied to the two-phase/three-phase coordinate converters 49A, 49B of the own system. given to

The two-phase/three-phase coordinate conversion units 49A, 49B use the rotor rotation angle θ calculated by the rotation angle calculation units 53A, 53B to obtain the d-axis command voltages v _d1 ^* , v _d2 ^* and the q-axis command voltage v _q1 . ^* , _vq2 ^* are converted into indicated voltages _vU1 ^* , _vV1 ^* , _vW1 ^* ; _vU2 ^* , _vV2 ^* , _vW2 ^* of the U, V, and W phases.

PWM control units 50A and 50B generate U-phase PWM control signals and V-phase PWM control signals having duty ratios corresponding to command voltages _vU1 ^* , _vV1 ^* , _vW1 ^* ; _vU2 ^* , _vV2 ^* , and _vW2 ^* , respectively. signal and a W-phase PWM control signal. The power elements forming the drive circuits 82 and 83 of each system are controlled by these PWM control signals. Thereby, the stator coils of each phase of each system are energized according to the command voltages _vU1 ^* , _vV1 ^* , _vW1 ^* ; _vU2 ^* , _vV2 ^* , _vW2 ^* .

Hereinafter, the forward rotation table 111a, the reverse rotation table 111b, and the comprehensive command value setting section 92 shown in FIG. 10 will be described in detail.

FIG. 12 is a schematic diagram showing a part of an example of contents of the normal conversion table 111a.

On the forward rotation table 111a, a comprehensive current command value _Ia,total ^* when the electric motor 18 is rotated in the forward direction, and a motor torque _Tm at the comprehensive current command value _Ia,total ^* are stored. A motor torque T _m [Nm] generated from the electric motor 18 is stored for each rotor rotation angle θ with respect to a combination with the maximum comprehensive phase angle command value β _total ^* . However, the forward rotation table 111a is set by the current command value setting units 42A and 42B based on the comprehensive current command value _{Ia, total} ^* and the comprehensive phase angle command value β _total ^* , and the above equations (15) and (16). are used to calculate armature current command values I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* .

In the example of FIG. 12, the N comprehensive current command values _Ia,total ^* have a relationship of _Ia,total ^* ₁ < _Ia,total ^* ₂ <... _Ia,total ^* _N . The _M rotor rotation angles .theta. are set in predetermined angular increments from 0.degree.

Such a forward rotation table 111a is created, for example, as follows. A predetermined comprehensive current command value _{Ia, total} ^* and a predetermined comprehensive phase angle command value β _total ^* are given to the current command value setting units 42A and 42B of the motor control circuit as shown in FIG. A code representing the forward rotation direction is given to the arithmetic units 43A and 43B. As a result, the global current command value _Ia,total ^* , the global phase angle command value _βtotal ^* , and the d-axis and q-axis current command values _id1 ^* , _iq1 ^* ; _id2 ^* corresponding to the sign , i _q2 ^* , the electric motor 18 is driven forward. The motor torque _Tm generated from the electric motor 18 and the rotor rotation angle θ are obtained while the electric motor 18 is driven to rotate forward. As a result, the motor torque _Tm for each rotor rotation angle θ is obtained with respect to the combination of the predetermined comprehensive current command value _Ia,total ^* and the predetermined comprehensive phase angle command value _βtotal ^* . The motor torque _Tm is measured using a measuring device (not shown).

By conducting such an experiment for each of _a plurality of comprehensive phase angle command values β _total ^{* ,} _it is ^possible to Data of the motor torque _Tm for each rotor rotation angle θ for each combination is obtained. Based on the data thus acquired, the comprehensive phase angle command value β _total ^* that maximizes the motor torque T _m with respect to the predetermined comprehensive current command value I _a,total ^* is specified.

By conducting the above-described experiment for each of a ^{plurality of comprehensive current command values I a, total *} _{, the} ^{comprehensive} current command value I _{a, total} ^* and the comprehensive phase angle command value β _total ^* for which the motor torque T _m is maximized, the data of the motor torque T _m for each rotor rotation angle θ is acquired. As a result, data for creating the normal rotation table 111a is obtained.

Although not shown, the reverse rotation table 111b stores a comprehensive current command value _Ia,total ^* when the electric motor 18 is rotated in the reverse direction, and the motor torque at the comprehensive current command value _Ia,total ^* . A motor torque T _m [Nm] generated from the electric motor 18 is stored for each rotor rotation angle θ with respect to the combination with the comprehensive phase angle command value β _total ^* that maximizes T _m .

The reverse rotation table 111b is produced by conducting experiments similar to those conducted to produce the forward rotation table 111a. However, when creating the reverse rotation table 111b, unlike the case of creating the forward rotation table 111a, the current vector calculation units 43A and 43B are given a sign indicating the reverse rotation direction during the experiment. As a result, the electric motor 18 is rotationally driven in the reverse direction during the experiment.

Next, the operation of the comprehensive command value setting section 92 will be described in detail. In the following description, the latest rotor rotation angle θ calculated by the rotation angle calculator 53A will be referred to as "current rotor rotation angle θ".

The comprehensive command value setting unit 92 first selects the rotation direction tables 111a and 111b from the forward rotation table 111a and the reverse rotation table 111b according to the sign of the motor torque command value _Tm ^* . Based on the selected tables 111a and 111b, the comprehensive command value setting unit 92 sets a comprehensive command value for causing the electric motor 18 to generate a motor torque corresponding to the motor torque command value _Tm ^* at the current rotor rotation angle θ. Set the global current command value I _{a, total} ^* and the global phase angle command value β _total ^* .

Specifically, the comprehensive command value setting unit 92 selects a motor torque command value having the same magnitude as the motor torque command value _Tm ^* from among a plurality of motor torques _Tm corresponding to the current rotor rotation angle θ in the selected tables 111a and 111b. Find the motor torque T _m for When the inclusive command value setting unit 92 can retrieve the motor torque _Tm having the same magnitude as the motor torque command value _Tm ^* , the inclusive command value setting unit 92 selects the inclusive command value corresponding to the motor torque _Tm from the tables 111a and 111b. The current command value _{Ia, total} ^* and the comprehensive phase angle command value β _total ^* are read out and set in the current command value setting units 42A and 42B.

On the other hand, when the motor torque _Tm having the same magnitude as the motor torque command value _Tm ^* cannot be retrieved, the comprehensive command value setting section 92 performs the following processing. The comprehensive command value setting unit 92 selects a motor torque command value smaller than and closest to the motor torque command value _Tm ^* from among a plurality of motor torques _Tm corresponding to the current rotor rotation angle θ in the selected tables 111a and 111b. A global current command value _Ia,total ^* and a global phase angle command value _βtotal ^* corresponding to the motor torque _Tm (hereinafter referred to as "first motor torque _Tm1 ") are read.

In addition, the comprehensive command value setting unit 92 selects the motor torque command value Tm* that is larger than the motor torque command value _Tm ^* and closest to it from among the plurality of motor torques _Tm corresponding to the current rotor rotation angle θ in the tables 111a and 111b. A global current command value _Ia,total ^* and a global phase angle command value _βtotal ^* corresponding to the motor torque _Tm (hereinafter referred to as "second motor torque _Tm2 ") are read. Then, the comprehensive command value setting unit 92 linearly interpolates the read two sets of comprehensive current command values I _{a, total} ^* and comprehensive phase angle command value β _total ^* to obtain the motor torque command value T _m ^*. A global current command value I _{a, total} ^* and a global phase angle command value β _total ^* corresponding to . As linear interpolation in this case, a method similar to the linear interpolation described in the embodiment of FIG. 3 can be used.

In this second modification, the synchronous reluctance motor can be controlled in consideration of the influence of the magnetic flux exerted on the rotor by the stator coil of the other system. Therefore, a synchronous reluctance motor having two systems of stator coils can be controlled with high efficiency.
[Third Modification]
A third modification of the ECU 12 will be described below. The ECU 12 according to the third modification is a control unit that controls a synchronous reluctance motor having two systems of stator coils, like the ECU 12 according to the second modification.

FIG. 13 is a schematic diagram showing the electrical configuration of a third modified example of the ECU. In FIG. 13, the same reference numerals as in FIG. 10 denote the parts corresponding to the parts in FIG. 10 described above.

The electric motor 18 is a synchronous reluctance motor including a first system stator coil 18A and a second system stator coil 18B.

A microcomputer 81 in the ECU 12 includes a torque command value setting portion 91, a torque command value distribution portion 192, a first system control portion 93A, and a second system control portion 93B. First system control unit 93A and second system control unit 93B include current command value setting units 142A and 142B, current vector calculation units 43A and 43B, and current feedback control units 94A and 94B.

The ECU 12 of FIG. 13 is provided with a torque command value distribution section 192 instead of the comprehensive command value setting section 92 in the ECU 12 of FIG. 13 is provided with current command value setting units 142A and 142B instead of the current command value setting units 42A and 42B of the ECU 12 of FIG. Further, in the ECU 12 of FIG. 13, the nonvolatile memory 40 includes a first memory 40A that stores a table used in the first system current command value setting unit 142A, and a second system current command value setting unit 142B. and a second memory 40B in which the tables used are stored. The first memory 40A and the second memory 40B may be formed within one nonvolatile memory 40, or may be configured from physically different nonvolatile memories. Other configurations of the ECU 12 in FIG. 13 are the same as those of the ECU 12 in FIG.

Tables stored in the torque command value distribution unit 192, the current command value setting units 142A and 142B, and the memories 40A and 40B will be described below.

Torque command value distribution unit 192 distributes motor torque command value T _m ^* set by torque command value setting unit 91 to current command value setting units 142A and 142B for the first and second systems. In this embodiment, the torque command value distribution unit 192 distributes the motor torque command value T _m ^* to each of the current command value setting units 142A and 142B in half. Therefore, if the torque command values given to current command value setting section 142A and current command value setting section 142B are respectively T _m1 ^* and T _m2 ^* , then T _m1 ^* = T _m2 ^* = T _m ^* /2.

The first memory 40A stores a normal table 121 that is used by the current command value setting unit 142A of the first system when the first and second systems are normal, and a normal table 121 that is used when the second system is abnormal. An abnormality table 122 used in the single-system current command value setting unit 142A is stored. Each of these tables 121, 122 includes forward rotation tables 121a, 122a and reverse rotation tables 121b, 122b.

The second memory 40B stores a normal table 131 that is used by the current command value setting unit 142B of the second system when the first and second systems are normal, and a normal table 131 that is used when the first system is abnormal. An abnormal table 132 used in the two systems of current command value setting units 142B is stored. Each of these tables 131, 132 includes forward rotation tables 131a, 132a and reverse rotation tables 131b, 132b.

FIG. 14A is a schematic diagram showing a part of an example of the contents of the forward rotation table 121a included in the normal table 121 for the first system, and FIG. FIG. 13 is a schematic diagram showing a part of an example of contents of a normal rotation table 131a.

The forward rotation tables 121a and 131a for the first and second systems are set to the armature current command value for the own system in the normal/forward rotation state in which the systems are simultaneously driven and the electric motor 18 is rotated in the forward rotation direction. It is a table for setting I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* . In the forward rotation tables 121a and 131a, the armature current command values _Ia1 ^* and _Ia2 ^* in the normal/forward rotation state and the motor torque _Tm at the armature current command values _Ia1 ^* and _Ia2 ^* are maximum. A motor torque T _m [Nm] generated from the electric motor 18 is stored for each rotor rotation angle θ with respect to a combination of the current phase angle command values β ₁ ^* and β ₂ ^* . However, the forward rotation tables 121a and 131a are created on the assumption that the motor torque command value T _m ^* is distributed to the current command value setting units 142A and 142B by 1/2 in the normal/forward rotation state. .

The forward rotation tables 121a and 131a are created, for example, based on the forward rotation table 111a (see FIG. 12) of the second modified example. Specifically, I _a1 ^* _i (i=1, 2, 3, . . . , N) in the normal rotation table 121a of FIG. 14A and I _a2 ^* _i (i=1, 2, 3, . . . , N) are set to 1/2 of the corresponding values of _Ia,total ^* _i (i=1, 2, 3, . . . , N) in the forward conversion table 111a of FIG.

Also, β ₁ ^* _i ( _i =1, ₂ , 3, . . . , N) in the normal rotation table 121a of FIG ^. , . . . , N), the corresponding values of β _total ^* _i (i=1, 2, 3, . . . , N) in the normal conversion table 111a of FIG.

Furthermore, as T _i,k (i=1, 2, 3, . . . , N; k=1, 2, 3, . 1/2 of the corresponding value of T _i,k (i=1, 2, 3, . . . , N; k=1, 2, 3, . . . , M) in the normal conversion table 111a is set. As a result, the forward rotation tables 121a and 131a are obtained.

The reverse rotation tables 121b and 131b included in the normal operation tables 121 and 131 can also be created by a similar method based on the reverse rotation table 111b of the second modified example.

The normal rotation tables 122a and 132a included in the abnormal tables 122 and 132 for the first and second systems are for abnormal/normal rotation in which only the own system of the two systems is driven and the electric motor 18 is rotated in the normal rotation direction. 2 is a table for setting armature current command values I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* in a forward rotation state;

Further, the reverse rotation tables 122b and 132b included in the abnormality tables 122 and 132 are set to the armature current command value _Ia1 in an abnormal/reverse rotation state in which only the own system is driven and the electric motor 18 is rotated in the reverse direction. ^* , I _a2 ^* and a table for setting current phase angle command values β ₁ ^* , β ₂ ^* .

The abnormal tables 122a, 122b, 132a, 132b have the same structure as the normal tables 121a, 121b, 131a, 131b, but the values _Ia1 ^* _i , _Ia2 ^* _i , β1* _i , β1 ^* _i , β ₂ ^* _i , T _i,k are different from the normal tables 121a, 121b, 131a, 131b. That is, in the abnormal state tables 122a, 122b, 132a, 132b, armature current command values I _a1 ^* , I _a2 ^* in an abnormal state in which only one of the two systems is driven, and the armature current command values _The ^motor _{torque Tm [} ^Nm _] ^generated from the electric ^motor 18 _is It is stored for each rotor rotation angle θ.

The abnormal tables 122 and 132 can be created by performing experiments similar to the case of creating the forward rotation table 61 and the reverse rotation table 62 in FIG. 6 with the other system stopped.

The current command value setting units 142A and 142B receive the motor torque command values T _m1 ^* and T _m2 ^* distributed by the torque command value distribution unit 192, the rotor rotation angle θ given from the rotation angle calculation units 53A and 53B, and an abnormality determination signal indicating whether or not the other system is abnormal.

The current command value setting units 142A and 142B set the command values as follows when the abnormality determination signal input thereto indicates that the other system is not abnormal (normal time). In other words, the current command value setting units 142A and 142B set the motor torque command values _Tm1 ^* and _Tm2 ^* , the rotor rotation angle θ, and the motor torque command values _Tm1 ^* and _Tm2 ^* for normal operation according to the signs of the motor torque command values Tm1* and Tm2*. Armature current command values I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* are set based on tables 121 (121a, 121b); 131 (131a, 131b).

On the other hand, when the abnormality determination signal input thereto indicates that the other system is abnormal (at the time of abnormality), the current command value setting units 142A and 142B set the command values as follows. In other words, the current command value setting units 142A and 142B set the motor torque command values T _m1 ^* and T _m2 ^* , the rotor rotation angle θ, and the motor torque command values T _m1 ^* and T _m2 ^* . Armature current command values I _a1 ^* , I _a2 ^* and current phase angle command values β ₁ ^* , β ₂ ^* are set based on tables 122 (122a, 122b); 132 (132a, 132b).

In this third modification, when the two systems are normal, the synchronous reluctance motor can be controlled by taking into account the influence of the magnetic flux exerted on the rotor by the stator coil of the other system. Therefore, a synchronous reluctance motor having two systems of stator coils can be controlled with high efficiency. In addition, in the third modification, when the other system is abnormal, the synchronous reluctance motor can be controlled without considering the influence of the magnetic flux that the stator coil of the other system exerts on the rotor. Therefore, it is possible to perform appropriate motor control even in the event of an abnormality.

Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms. In the above-described embodiment, the microcomputer 31 (81) includes the voltage limiting section 48 (48A, 48B), but may not include the voltage limiting section 48 (48A, 48B).

Further, in the above-described embodiment, a synchronous reluctance motor capable of rotating in both forward and reverse directions has been described, but the present invention is also applicable to an electric synchronous reluctance motor that rotates in only one direction. be able to.

In the above-described embodiment, the electric motor 18 is a synchronous reluctance motor. reluctance motor, IPM motor, etc.).

Further, in the above-described embodiment and the first modification, the armature current/current phase angle setting tables 61 and 62 (see FIGS. 3 and 7) include the armature current command value I _a ^* and the current phase angle command value The motor torque _Tm generated from the electric motor 18 is stored for each rotor rotation angle θ with respect to the combination with β ^* . However, in the _armature current/current phase angle setting tables ⁶¹ and 62, regardless of the rotor rotation angle ^θ , the electric motor 18 _may be stored. The same applies to the tables 111, 121, 122, 131 and 132 used in the second and third modifications.

Also, in the above description, an embodiment in which the present invention is applied to an electric motor control device for an electric power steering device has been described. However, the present invention can be applied to a motor control device other than an electric motor control device for an electric power steering system, as long as it is a control device for a motor that is controlled based on a motor torque command value.

Although the embodiments of the present invention have been described in detail, these are merely specific examples used to clarify the technical content of the present invention, and the present invention should be construed as being limited to these specific examples. should not, the scope of the invention is limited only by the appended claims.

This application corresponds to Japanese Patent Application No. 2017-140127 filed with the Japan Patent Office on July 19, 2017, and the entire disclosure of that application is incorporated herein by reference.

12... ECU, 18... Electric motor, 25... Rotation angle sensor, 31, 81... Microcomputer, 40... Non-volatile memory, 41, 91... Torque command value setting section, 42, 142, 142A, 142B... Current command value setting Part 43, 43A, 43B... Current vector calculation part 5353A, 53B... Rotation angle calculation part 54... Rotation speed calculation part 61, 71, 111a, 121a, 122a, 131a, 132a... Normal rotation table 62, 72 , 111b, 121b, 122b, 131b, 132b... reversing table, 92... comprehensive command value setting section, 192... torque command value distribution section

Claims (7)

A control device for controlling a motor using reluctance torque,
rotation angle detection means for detecting the rotor rotation angle of the motor;
a table storing the motor torque generated by the motor with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value;
a first setting unit that sets a motor torque command value that is a command value of the motor torque to be generated by the motor;
A second setting unit for setting, based on the table, an armature current command value and a current phase angle command value for causing the motor to generate motor torque corresponding to the motor torque command value set by the first setting unit. includingfruit,
The table stores the motor torque generated by the motor for each rotor rotation angle with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value. death,
The second setting section is an armature for causing the motor to generate a motor torque corresponding to the motor torque command value set by the first setting section at the detected rotor rotation angle detected by the rotation angle detection means. setting a current command value and a current phase angle command value based on the table; motor controller. A control device for controlling a motor using reluctance torque,
a table storing the motor torque generated by the motor with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value;
a first setting unit that sets a motor torque command value that is a command value of the motor torque to be generated by the motor;
A second setting unit for setting, based on the table, an armature current command value and a current phase angle command value for causing the motor to generate motor torque corresponding to the motor torque command value set by the first setting unit. When,
a table for reducing torque fluctuations comprising the table;
a high output table storing combinations of armature current command values and current phase angle command values that provide maximum motor torque for each rotational speed of the motor;
The second setting unit selects one of the torque fluctuation reduction table and the high output table according to the rotation speed of the motor, and uses the selected table to set an armature current command value and a current phase. A motor controller configured to set an angular command value . A control device for controlling a motor using reluctance torque,
a table storing the motor torque generated by the motor with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value;
a first setting unit that sets a motor torque command value that is a command value of the motor torque to be generated by the motor;
A second setting unit for setting, based on the table, an armature current command value and a current phase angle command value for causing the motor to generate motor torque corresponding to the motor torque command value set by the first setting unit. and
The motor is a reluctance torque-utilizing motor having two stator coils,
The table shows the combination of a comprehensive armature current command value that includes the two systems and a current phase angle command value that maximizes the motor torque in the comprehensive armature current command value. It stores the motor torque generated from
The second setting unit is configured to distribute a comprehensive armature current command value set based on the table to each system,
A motor control device for controlling a current supplied to a stator coil of each system based on the distributed armature current command value for each system and the current phase angle command value set by the second setting unit. . A control device for controlling a motor using reluctance torque,
a table storing the motor torque generated by the motor with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value;
a first setting unit that sets a motor torque command value that is a command value of the motor torque to be generated by the motor;
A second setting unit for setting, based on the table, an armature current command value and a current phase angle command value for causing the motor to generate motor torque corresponding to the motor torque command value set by the first setting unit. and
The control device is a control device for controlling a reluctance torque-based motor having two stator coils,
further comprising a torque command value distribution unit that distributes the motor torque command value set by the first setting unit into a motor torque command value for the first system and a motor torque command value for the second system,
The table includes a table for the first system and a table for the second system,
The second setting unit uses the table for the first system and the motor torque command value for the first system to set an armature current command value and a current phase angle command value for the first system. A system command value setting unit, a table for the second system, and a motor torque command value for the second system are used to set an armature current command value and a current phase angle command value for the second system. including a command value setting unit for two systems,
Based on the armature current command value and the current phase angle command value for the first system, the current supplied to the stator coil of the first system is controlled, and the armature current command value and the current phase angle for the second system are controlled. A motor control device in which a current supplied to a second system stator coil is controlled based on an angular command value . When the second system is abnormal, the first system command value setting unit uses a second system abnormality table different from the first system table to set the electric machine for the first system. configured to set a child current command value and a current phase angle command value,
When the first system is abnormal, the second system command value setting unit uses a first system abnormality table that is different from the second system table to set the electric machine for the second system. 5. The motor control device according to claim 4 , configured to set a child current command value and a current phase angle command value . further comprising rotation angle detection means for detecting the rotor rotation angle of the motor;
The table stores the motor torque generated by the motor for each rotor rotation angle with respect to the combination of the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value. death,
The second setting section is an armature for causing the motor to generate a motor torque corresponding to the motor torque command value set by the first setting section at the detected rotor rotation angle detected by the rotation angle detection means. 6. The motor control device according to claim 2 , wherein the current command value and the current phase angle command value are set based on the table . The table is
generated from the motor with respect to a combination of an armature current command value and a current phase angle command value that maximizes the motor torque at the armature current command value when the motor is rotated in the first rotation direction a first table storing the motor torque for each rotor rotation angle;
When the motor is rotated in the second direction opposite to the first direction, the armature current command value and the current phase angle command value that maximizes the motor torque at the armature current command value. a second table storing the motor torque generated by the motor for each rotor rotation angle for each combination,
The second setting unit
When the torque direction of the motor torque command value is the first rotation direction, an armature current command value and an armature current command value for causing the motor to generate motor torque corresponding to the motor torque command value at the detected rotor rotation angle; setting a current phase angle command value based on the first table;
When the torque direction of the motor torque command value is the second rotation direction, an armature current command value and an armature current command value for causing the motor to generate motor torque corresponding to the motor torque command value at the detected rotor rotation angle; 7. The motor control device according to claim 1 , wherein the current phase angle command value is set based on said second table .

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